The objective of this research is to improve the evaluation of left ventricular function in patients with coronary heart disease using left ventriculography. Impairment of myocardial contraction is now judged subjectively by the radiologist or cardiologist viewing a cine left ventriculogram. The viewer can fail to detect, or can misjudge, the severity of pathology. In addition, there is considerable intra- and inter-observer variation among results. A simple, objective means of detecting and measuring myocardial contraction is needed. We have developed such a method and tested it in a small group of patients. We propose to evaluate it in an adequately large group of patients with and without myocardial pathology and impairment of segmental contraction. Our method includes: (1) a technique for improved superimposition of the left ventricular silhouettes traced at end diastole and end systole, which corrects for the rotation of the heart during contraction; (2) a simple method of determining the segmental contraction of the ventricle from the superimposed silhouettes. The technique will be applied to cine left ventriculograms taken at rest and after stress. The results of the evaluation of impaired segmental contraction will be compared with the patient's coronary angiogram and the results from regional myocardial perfusion measurements. The study can provide an objective measure of ventricular function. It can detect impaired segmental contraction, measure its severity, help the physician select the therapy which has the greatest chance of benefitting the patient, help predict the outcome of the therapy, and evaluate the effect of the treatment on the patient's ventricular function.